Terence O'Reilly, from South Elmsall near Pontefract, was aged 78 when he was jailed at Leeds Crown Court on January 16 2017 after admitting 17 sexual offences against two victims.
The offences, which included six charges of rape against a child, took place from the 1960s to the 1990s.
An inquest at Wakefield heard O'Reilly suffered from blood and lymph cancer and told prison staff at Armley that he was only expected to live for nine months.
O'Reilly, who was at high risk of infection, was placed in a single cell at Armley and was taken to St James's Hospital for treatment on five occasions before he died aged 79 at the hospital on April 21 2017.
Dr Leslie Davidson conducted the post mortem and concluded that he died of bone marrow cancer multiple myeloma and blood cancer myelodysplastic syndrome.
The inquest was told O'Reilly was handcuffed while being taken to hospital on the first three of the five occasions and that the Prisons and Probation Ombudsman were concerned.
Reading a report from the Ombusdman, area coroner Jonathan Leach said: "We consider the restraint was disproportionate given his advanced age and poor health."
Mr Leach said the Ombudsman made a recommendation that all staff take into account a prisoner's health and actual risk posed at the time.
Mark Scott, a governor at Armley and head of security at the jail told the inquest: "I think we made the appropriate decision at the time to evaluate the risks posed."
Mr Scott added: "Ultimately our role is to protect the public, to evaluate the risk that individual poses to the public and the risk that individual may pose of potential escape."
Mr Scott said the issue was constantly reviewed and said that handcuffs were not used after Mr O'Reilly's condition deteriorated.
Recording a verdict of death by natural causes, area coroner Jonathan Leach, said "I'm mindful they (the prison service) have a difficult line to tread in the sense they have to ensure the public are kept safe and at the same time allowing he prisoner, in this case Mr O'Reilly, the dignity one would expect.
"On the last two occasions he was admitted to hospital there were no restraints used. I'm satisfied that in this case the appropriate decisions were made."
The offences O'Reilly pleaded guilty to were three indecency offences, two indecent assaults, six rape offences and three other sexual offences.
He also pleaded guilty to three sexual offences against another young girl in the South Kirkby area.
Police investigations began in early 2015 after one of the victims disclosed the sexual abuse she had suffered.
O'Reilly was questioned and, following investigation, charged in early 2016 with multiple sexual offences.
Speaking after O'Reilly's sentencing hearing in January 2017, Detective Inspector Vanessa Rolfe, of Wakefield District CID, said: "We welcome the very significant sentence given to O'Reilly today for what were absolutely shocking crimes perpetrated against innocent young girls who were in no position to defend themselves or resist.
"He displayed utter wickedness in his actions and the fact that he received such a significant sentence despite his age and guilty plea reflects just how abhorrent his behaviour has been.
"The courage his victim's have shown in coming forward and assisting our investigation must clearly be commended.
"I hope seeing O'Reilly receive a sentence which will most likely see him spend the rest of his life behind bars will bring them at least some sense of closure in seeing justice done."